Two-Phase fluid - Weird Temperature peak

Hi people,

I am trying that really nice SimScape two-phase fluid library.

I am simulating a double acting steam free piston.

It is running without errors (most of the time, depends a lot on the valve pipe diameter I set ...), but the weird thing is when I increase the reservoir volume, the temperature suddenly shows really high peak in the beginnnig of the stroke (like if it was overheated steam).

Which is pretty surprising since I would expect a rise of pressure when the piston compress the fresh steam, not temperature ?

And the peak to be lower and lower when volume increase, but it is the contrary happening.

Any idea why is it happening ? It doesn't seems right to me.

Thank !

[Joris Naudin]

up

It's old but still there -_-'

[Luke Halberstadt]

When I run the simulation, it errors out at the beginning, so I do not see the behavior you are describing.

Caused by:

• ['Test/Solver Configuration']: At time 0.001059, one or more assertions are triggered. See causes for specific information.
• Pressure at the restriction must be greater than or equal to Minimum valid pressure. The assertion comes from: Block path: Test/NPI ENGINE/INLET VALVE - AAssert location: o In between line: 167, column: 9 and line: 167, column: 15 in file: C:\Program Files\MATLAB\R2020b\toolbox\physmod\simscape\library\m\+foundation\+two_phase_fluid\+elements\variable_local_restriction.ssc

Before addressing that issue, I would first eliminate all algebraic loops as it will improve overall simulation behavior.

Remove Algebraic Loops - MATLAB & Simulink (mathworks.com)